Truck hoist



-May 28, 1957 Filed May 16, 1955 H. 2. SMITH ETAL 2,793,767

TRUCK I-IOIST 5 Sheets-Sheet l INVENTOR HAROLD Z. SMITH JAMES H. SPARKS ATTORNEY H. Z. SMITH ETAL TRUCK HOIST 3 Sheets-Sheet 2 HAROLD z. SMITH 2 $QW0K ATTORNEY May 28, 1957 Filed May 16, 1955 y. "N u.

y 8, 1957 H. 2. SMITH EI'AL 2,793,767

TRUCK HOIST Filed May 16, 1955 s Sheets-Sheet 3 V In! |4 INVENTORS HARQLD 2; SMITH JAMES H. SPARKS ATTORNEY TRUCK HOIST Harold Z. Smith, Franklin, Tenn., and James H. Sparks, Tupelo, Miss.; said Sparks assignor to said Smith Application May 16, 1955, Serial No. 508,359

1 Claim. (Cl. 214-4634) The present invention relates to hydraulic hoist mechanism and in particular to a lift for elevating the front end of an auto truck or vehicle for rear end dumping or to facilitate access to the under portion thereof.

An object of the invention is to provide a simple, rugged, inclined plane lift assembly that may be shifted bodily to different locations with ease, and which requires only conventional connection with a hydraulic fluid power source to be fully serviceable.

Other and incidental objects will be apparent from the following description in conjunction with the accompanying drawings, in which:

Figure 1 is a side elevation of a service application of the hoist in raised position;

Figure 2 is a side elevation, partly in section, of the hoist in lowered position;

Figure 3 is a top plan view of the collapsed hoist;

Figure 4 is substantially a central vertical sectional View longitudinally through the hoist in raised position;

Figure 5 is an end elevation viewed from the right of Fig. 4;

Figure 6 is a vertical sectional view taken substantially on the line 66 of Fig. 4.

Convenient assembly, illustrative but not restrictive, is herein shown and described as one specific embodiment of the invention. It comprises a base frame 10 and a tiltable lift frame 11 pivoted at one end to an end of the base frame for oscillation in a vertical are by means of a hydraulic pressure motor 12 carried by the base frame and having an operating linkage 13 connected to the tilt frame.

The base frame includes a pair of parallel, laterally spaced angle iron side bars 14 with outwardly directed base flanges rigidly connected by angle iron end pieces 15 and braces 16 extending transversely therebetween; together constituting a horizontal ground engaging flat base. The tilt frame similarly includes a pair of parallel, laterally spaced channel iron side bars 17 with outwardly directed flanges rigidly connected by channel iron end pieces 18 and braces 19 extending transversely therebetween. The side bars 17 are spaced somewhat farther apart than the upstanding flanges of the base frame side bars 14 so that they override the base flanges of the bars 14 when the assembly is fully collapsed as shown in Fig. 3.

The tilt frame 11 further includes a platform for the front wheels of a truck or other vehicle. This platform is constituted by a tread plate 20 laterally outward from and extending along the full length of each side bar 17. The tread plates are suitably dimensioned as to spacing and width to accommodate the vehicle wheels, and each is provided with an inside guard rail 21 which may conveniently be a metal strip welded to the plate edge and curved inwardly at each end into a weld attachment to the adjacent side bar 17 of the tilt frame. The tread plates are rigidly attached to the tilt frame by welding to the frame end bars and by a plurality of appropriately nited States Patent 0 located metal strut brace assemblies 22 welded to the under face of each tread plate and to the adjacent frame side bars 17.

Each tilt frame side bar at one end has a pivotal connection 23 with the adjacent end of its corresponding base frame side bar 14. This connection preferably is a cross shaft carried by supports 24 on the base frame end piece 15. The ends of the shaft are passed freely through the adjacent pairs of side bars and journal the ends of the tilt frame side bars 17.

Positioned centrally between the side bars of the base frame is a motor support consisting of a sub frame having a pair of longitudinal channel iron sid-e bars 25 in parallel spaced relation with their ends seated on and welded to the braces 16 of the base frame. The ends of the bars 25 nearest the pivotal connection of the tilt frame mount between them a transverse shaft 26 on which are journalled bearings 27 fixed to the ends of a pair of lift levers 28. Each lever is adapted for oscillation in a vertical plane between the adjacent side bars 14 and 25 of the base and sub frames, respectively, and is pivotally connected at its other end to the adjacent end of a link 29. This link has at its other end a pivotal connection to an element of the tilt frame, in this case a saddle frame designated generally as 30 secured transversely between and to the tilt frame side bars 17.

Motive power for operating the tilt frame is supplied from a hydraulic pressure cylinder 31 having a double acting piston whereof the rod 32 carries a cross head 33 provided at each end with an anti-friction roller 34. Each roller bears upon a cam track or guideway 35 on the adjacent lift lever 28 and is located outwardly alongside another anti-friction roller 36 carried by the cross head and which bears on the face of an upright cam 37 that is mounted in a fixed position on the adjacent side bar 25 of the motor support frame between the motor cylinder and the pivot shaft 26, with the low point of the cam nearest the end of the cylinder. The opposite end of the cylinder has conduit connections 38 and 39 leading to a hydraulic pressure supply source, not shown, and has a pivotal connection 40 with the adjacent end of the motor support frame.

Normally, when the hoist is collapsed as in Figs. 2 and 3, the piston cross head 33 is retracted and its inner rollers 36 are seated against the motor support frame side bars adjacent the low points of the fixed cams 37 and with the rollers 34 at the inner limit of their guideways 35. Upon a protractile stroke of the piston rod 32 the cross head rollers 36 ride up on the cams 37 and at the same time the rollers 34 move outwardly along their guideways and correspondingly swing the lift levers 28 upwardly. Upward travel of these levers is transmitted to the amplifying links 29 which in turn elevate the tilt frame. A retractile stroke of the piston rod pulls the parts back to their initial collapsed position with the tilt frame nested flatly upon the base frame.

We claim:

In a vehicle dumping mechanism a base frame, a tilt frame nestable flatly thereon, said tilt frame including outwardly projecting side bars, a wheeled vehicle tread plate on each set of side bars adapted to receive the front wheels and adjacent portion of a dump vehicle, a pivotal connection between the frames at one end thereof, a fluid pressure responsive motor including a cylinder having a fixed pivotal connection with the base frame and having a piston including a cross head, linkage between and in pivotal connection with both frames at each side thereof, said linkage including lift levers fulcrumed on the base frame to lie between said frames when they are nested, a pivotal and slidable connection between the References Cited in the file of this patent UNITED STATES PATENTS Rolf Aug. 8, 1950 Golay June 5, 1951 Lawless Sept. 11, 1951 Hutchinson Ian. 8, 1952 

